How do you update a CoreData entry that has already been saved in Swift?

Question

I\'m not sure what I\'m doing wrong here, but when I save the first time into coredata, it works just fine. When I try to overwrite that, it doesn\'t.

func t         


        

Answer 1

Step:1 - create new project and select "Use Core Data" go through : "https://medium.com/@ankurvekariya/core-data-crud-with-swift-4-2-for-beginners-40efe4e7d1cc"

Step:2 - Inside ViewController (userList)

import UIKit
import CoreData

class ViewController: UIViewController, UITableViewDelegate , UITableViewDataSource {

var arrUser = Array()
@IBOutlet var tableView: UITableView!

override func viewDidLoad() {
    super.viewDidLoad()

    self.title = "User List"
    self.tableView.separatorStyle = .none
    self.retrieveData(Delete: false, indexpath: 0)

    let logoutBarButtonItem = UIBarButtonItem(image: UIImage(named: "addImage"), style: .done, target: self, action: #selector(addNewUser))
    self.navigationItem.rightBarButtonItem  = logoutBarButtonItem
}

override func viewDidAppear(_ animated: Bool)
{
    super.viewDidDisappear(animated)
    self.retrieveData(Delete: false, indexpath: 0)
}

@objc func addNewUser(){
    let userVC = self.storyboard?.instantiateViewController(withIdentifier: "AddUser_VC") as! AddUser_VC
    self.navigationController?.pushViewController(userVC, animated: true)
}

//MARK: - TableView DataSource Delegate
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return self.arrUser.count
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

    let cell = tableView.dequeueReusableCell(withIdentifier: "UserCell") as! UserCell
    cell.selectionStyle = .none
    let dictData = self.arrUser[indexPath.row] as? NSManagedObject
    cell.lblName.text = dictData?.value(forKey: "name") as? String ?? ""
    cell.lblPost.text = dictData?.value(forKey: "post") as? String ?? ""
    cell.lblEmail.text = dictData?.value(forKey: "email") as? String ?? ""
    cell.lblPhone.text = String(dictData?.value(forKey: "phone") as? Int ?? 0)
    cell.imageData?.image =  UIImage(data: dictData?.value(forKey: "image") as? Data ?? Data())

    return cell
}

func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    return 140
}

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {

    let dictData = self.arrUser[indexPath.row] as? NSManagedObject
    let AddUserVC = self.storyboard?.instantiateViewController(withIdentifier: "AddUser_VC") as! AddUser_VC
    AddUserVC.isEdit  = true
    AddUserVC.dictObj = dictData
    self.navigationController?.pushViewController(AddUserVC, animated: true)

}

func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
    return true
}

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
    if (editingStyle == .delete) {
        //self.deleteData(indexpath: indexPath.row)
        self.retrieveData(Delete: true, indexpath: indexPath.row)
    }
}

//MARK: - retrieveData
func retrieveData(Delete:Bool , indexpath:Int) {

    guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else { return }
    let managedContext = appDelegate.persistentContainer.viewContext
    let fetchRequest = NSFetchRequest(entityName: "UserTable")

    if (Delete == true)
    {
        do
        {
            let test = try managedContext.fetch(fetchRequest)

            let objectToDelete = test[indexpath] as! NSManagedObject
            managedContext.delete(objectToDelete)

            do{
                try managedContext.save()
                self.retrieveData(Delete: false, indexpath: 0)
            }
            catch
            {
                print(error)
            }
        }
        catch
        {
            print(error)
        }
    }

    do {
        self.arrUser = try managedContext.fetch(fetchRequest)
        self.tableView.reloadData()
        print(self.arrUser)
    } catch {
         print("Failed")
    }
}
}

Step:3 - Inside UserCell

import UIKit

class UserCell: UITableViewCell {


@IBOutlet var lblName: UILabel!
@IBOutlet var lblEmail: UILabel!
@IBOutlet var lblPost: UILabel!
@IBOutlet var lblPhone: UILabel!
@IBOutlet var imageData: UIImageView!

override func awakeFromNib() {
    super.awakeFromNib()
    self.imageData.layer.cornerRadius = self.imageData.frame.height / 2
    self.imageData.layer.borderWidth = 1.0
    self.imageData.layer.borderColor = UIColor.lightGray.cgColor
    self.imageData.layer.masksToBounds = true
}

override func setSelected(_ selected: Bool, animated: Bool) {
    super.setSelected(selected, animated: animated)

    // Configure the view for the selected state
}

}

Step:4 - Inside AddUserVC

import UIKit
import CoreData

class AddUser_VC: UIViewController ,UIImagePickerControllerDelegate ,UINavigationControllerDelegate {

var dictObj: NSManagedObject!
var isEdit:Bool = false

@IBOutlet var imageData: UIImageView!
@IBOutlet var txtName: UITextField!
@IBOutlet var txtEmail: UITextField!
@IBOutlet var txtPost: UITextField!
@IBOutlet var txtPhone: UITextField!

@IBOutlet var btnAddUser: UIButton!


override func viewDidLoad() {
    super.viewDidLoad()

    self.imageData.layer.cornerRadius = self.imageData.frame.height / 2
    self.imageData.layer.borderWidth = 1.0
    self.imageData.layer.borderColor = UIColor.lightGray.cgColor
    self.imageData.layer.masksToBounds = true

    let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(imageTapped(tapGestureRecognizer:)))
    self.imageData.isUserInteractionEnabled = true
    self.imageData.addGestureRecognizer(tapGestureRecognizer)

    if (self.isEdit == true)
    {
        self.txtName.text = dictObj.value(forKey: "name") as? String ?? ""
        self.txtEmail.text = dictObj.value(forKey: "email") as? String ?? ""
        self.txtPost.text = dictObj.value(forKey: "post") as? String ?? ""
        self.txtPhone.text = String(dictObj.value(forKey: "phone") as? Int ?? 0)
        self.imageData?.image = UIImage(data: dictObj?.value(forKey: "image") as? Data ?? Data())
        self.btnAddUser.setTitle("UPDATE", for: .normal)
    }
}


//MARK: - btnAddUserAction Method -
@IBAction func btnAddUserAction(_ sender: Any) {

    let arrData = [self.txtName,self.txtEmail,self.txtPost,self.txtPhone]
    for txt in arrData
    {
        if (txt?.text == "")
        {
            let alert = UIAlertController(title: "Alert", message: "Please Enter All Fields", preferredStyle: UIAlertController.Style.alert)
            alert.addAction(UIAlertAction(title: "Click", style: UIAlertAction.Style.default, handler: nil))
            self.present(alert, animated: true, completion: nil)
            return
        }
    }

    self.createData()
}

//MARK: - Image Tap Method -
@objc func imageTapped(tapGestureRecognizer: UITapGestureRecognizer)
{
    let alert = UIAlertController(title: "Choose Image", message: nil, preferredStyle: .actionSheet)
    alert.addAction(UIAlertAction(title: "Camera", style: .default, handler: { _ in
        self.openCamera()
    }))

    alert.addAction(UIAlertAction(title: "Gallery", style: .default, handler: { _ in
        self.openGallery()
    }))

    alert.addAction(UIAlertAction.init(title: "Cancel", style: .cancel, handler: nil))

    self.present(alert, animated: true, completion: nil)
}

func openCamera()
{
    if UIImagePickerController.isSourceTypeAvailable(UIImagePickerController.SourceType.camera) {
        let imagePicker = UIImagePickerController()
        imagePicker.delegate = self
        imagePicker.sourceType = UIImagePickerController.SourceType.camera
        imagePicker.allowsEditing = false
        self.present(imagePicker, animated: true, completion: nil)
    }
    else
    {
        let alert  = UIAlertController(title: "Warning", message: "You don't have camera", preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
        self.present(alert, animated: true, completion: nil)
    }
}

func openGallery()
{
    if UIImagePickerController.isSourceTypeAvailable(UIImagePickerController.SourceType.photoLibrary){
        let imagePicker = UIImagePickerController()
        imagePicker.delegate = self
        imagePicker.allowsEditing = true
        imagePicker.sourceType = UIImagePickerController.SourceType.photoLibrary
        self.present(imagePicker, animated: true, completion: nil)
    }
    else
    {
        let alert  = UIAlertController(title: "Warning", message: "You don't have permission to access gallery.", preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
        self.present(alert, animated: true, completion: nil)
    }
}


func imagePickerController(_ picker: UIImagePickerController,
                           didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
    guard (info[.originalImage] as? UIImage) != nil else {
        fatalError("Expected a dictionary containing an image, but was provided the following: \(info)")
    }
     self.imageData.image = info[.originalImage] as? UIImage
    picker.dismiss(animated: true, completion: nil)
}

//MARK: - createData
func createData(){

    guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else { return }
    let managedContext = appDelegate.persistentContainer.viewContext
    let userEntity = NSEntityDescription.entity(forEntityName: "UserTable", in: managedContext)!

    var user = NSManagedObject()
    if(isEdit == true)
    {
         user = self.dictObj
    }
    else
    {
        user = NSManagedObject(entity: userEntity, insertInto: managedContext)
    }

    let image = self.imageData.image!.jpegData(compressionQuality: 0.5)as NSData?
    user.setValue(self.txtName.text, forKeyPath: "name")
    user.setValue(self.txtEmail.text, forKey: "email")
    user.setValue(self.txtPost.text, forKey: "post")
    user.setValue(Int(self.txtPhone.text!), forKey: "phone")
    user.setValue(image, forKey: "image")

    do {
        try managedContext.save()
        self.navigationController?.popViewController(animated: true)

    } catch let error as NSError {
        print("Could not save. \(error), \(error.userInfo)")
    }
}

} 

Alternate Methods:

//MARK: - CoreData Methods -
func createData(){
    guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else { return }
    let managedContext = appDelegate.persistentContainer.viewContext
    let userEntity = NSEntityDescription.entity(forEntityName: "Movie", in: managedContext)!
    for obj in self.MoviewList.arrMovieData{
        let user = NSManagedObject(entity: userEntity, insertInto: managedContext)
        user.setValue(obj.id, forKey: "id")
        user.setValue(obj.title, forKey: "title")
        user.setValue(obj.overview, forKey: "overview")
        let url = API.IMAGE_BASE_URL + obj.poster_path
        user.setValue(url, forKey: "poster_path")
   }
    do {
        try managedContext.save()
    } catch let error as NSError {
        print("Could not save. \(error), \(error.userInfo)")
    }
}


func retrieveData() {

    guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else { return }
    let managedContext = appDelegate.persistentContainer.viewContext
    let fetchRequest = NSFetchRequest(entityName: "Movie")
    do {
        let result = try managedContext.fetch(fetchRequest)
        var arr = [[String:AnyObject]]()
        for data in result as! [NSManagedObject] {
            var obj = [String:AnyObject]()
            obj["id"] = data.value(forKey: "id") as AnyObject
            obj["title"] = data.value(forKey: "title") as AnyObject
            obj["overview"] = data.value(forKey: "overview") as AnyObject
            obj["poster_path"] = data.value(forKey: "poster_path") as AnyObject
            arr.append(obj)
        }
        self.MoviewList = MovieDataList(data: arr)
        self.tableView.reloadData()
    } catch {

        print("Failed")
    }
}

func deleteAllRecords() {
    let delegate = UIApplication.shared.delegate as! AppDelegate
    let context = delegate.persistentContainer.viewContext

    let deleteFetch = NSFetchRequest(entityName: "Movie")
    let deleteRequest = NSBatchDeleteRequest(fetchRequest: deleteFetch)

    do {
        try context.execute(deleteRequest)
        try context.save()
        self.createData()
    } catch {

    }
}